Vacuum controlled air vent



Feb. 12, 19 52 P. H. FITZGERALD 2,585,236

VACUUM CONTROLLED AIR VENT Filed April 6, 1950 Patented Feb. 12, 1952 2,585,236 VACUUM CONTROLLED AIR VENT Paul H. Fitzgerald, Rockford, Ill., assignor of'fivetwclfths to Harold J. Stoner, Rockford, Ill.

Application April 6, 1950, Serial No. 154,354

14 Claims. (01.123-119) This invention relates to a. vacuum controlled air vent for use in connection with a carburetor and its attached air cleaner on an internal combustion engine, as, for example, in an automobile.

The principal object of my invention is to provide an automatically openable and closeable air vent in the top of the air cleaner shell in close proximity to the carburetor intake, where hot gases delivered through the carburetor intake from the engine would otherwise be trapped when the engine is stopped, whereby to avoid diiiiculties in restarting, due to an enriched or flooding condition, assuming the effort to start again is made while the engine is still hot and before the trapped hot gases referred to have had an opportunity to be cooled off, or be dissipated, or escape.

Another object is to provide a flap valve for closing said air vent operatively connected with a spring-pressed plunger working in a small cylinder that has a small air vent or bleeder hole in one end behind the piston of said plunger and has connection at its other end through a spring-seated check valve with the intake manifold of the engine, whereby said flapvalve is automatically closed when the engine is started, and opens automatically only when the engine is actually stopped, any sudden drop in vacuum, due to opening the throttle suddenly, being insufficient to cause the valve to open, becauseof the seating of the check valve in the suction line extending to the manifold.

Another object is to provide a flap valve for the purpose described, which is so connected and operated that it can be applied to air cleaners of various shapes and designs and will not interfere with the operation of a hand controlled choke or an automatic choke, and, while primarily in,- tended for improving starting in hot weather, will not interfere with or complicate starting of the engine in cold weather.

The invention is illustrated in the accompanying drawing, in which;

Fig. 1 is a plan view of a carburetor and attached air cleaner on which'a vacuum controlled air vent is applied in accordance with my invention;

Fig. 2 is a front view of Fig. 1, on a larger scale;

Fig. 3 is a side view of Fig. 2, and,

Fig. 4 is a section on the line A-A o1 Fig. 1 showing the flap valve opened, said valve being shown in closed position in the other three views.

l he same reference numerals are applied to corresponding parts throughout the views.

Referring to the drawing, the reference nu- 2 J1 meral l designates the air cleaner, 2 the carbure'e tor, and 3 the working cylinderfor the spring? pressed plunger 9- that operates the flap valve 4 controlling the air vents ll provided in the top wall of the horizontally extending portion 23 of the air cleaner. The flap valve 4 is hinged at IE to the wall of the air cleaner, the hinges being fastened suitably by means of screws 33'. The plunger 9 has a laterally extending pivot pin projection I0 which is pivotally connected to an extension on one end of the flap valve 4. The cylin-.- der 3 is oscillatory mounted relativeto the car.- buretor 2 on a bracket l4 that is clamped as indicated at 34-35 to a plate 2|! suitably secured'to the carburetor and extending laterally therefrom; i3 is a nipple threaded into the lower end'plate of cylinder 3. To this nipple is threaded another nipple 5, the reduced end 12 of which is suitably connected by means of a flexible hose or tubing 40 with the intake manifold 4| of the engine, A coiled compression spring 8 housed in the cylinder 3 tends normally to hold the plunger 9 in the retracted position shown in Fig. 4 with the piston 3| thereof disposed in the upper endof the cylinder adjacent the air vent or bleederhole 36 provided in that end plate of the cylinder. However, whenthe engine is started andthere is a reduction in pressure in the intake'manifold 4|, the piston 3| is forced downwardly by air pressure, against the resistance of spring 8, thereby closing the flap valve 4 and sealing the air vents H, the flap valve 4 having. a layer of gasket material 22 on the under side thereof to insure an air-tight joint when the valve 4 is closed. A check valve I 1 is provided in the nipple 5 normally urged toward the fiat end of nipple I 3 as a seat by a coiled compression spring l8 which'in turn has abutment with an annular shoulder IS in the bore of the nipple 5. Hence, when the flap valve 4 is closed, it cannot open suddenly due to a sudden change in the reduction in pressure in the manifold 4|, as by reason of a sudden opening of the throttle. The valve ii, in other words, is unseated only when there is a sufiicient reduction in pressure in manifold M, and, otherwise, it is seated under action of spring is to retard return of the piston 3| under action of spring 8. I

The air cleaner in connection with which the vacuum controlled air vent is provided may be of any suitable or preferred type, the cleaner I being of a well known design in which the air is taken in through the annular opening 42 de fined within the rim of a removable dirt collecting cup 43 for passage first downwardly on the outside of the body 44 and then upwardly in the body 44, so that a good portion of the dirt in the air will be deposited in the cup 43. The air takes a right angle turn to flow from the body 44 through the lateral extension 45, whereby to aflord a further opportunity for dirt particles to be deposited in body 44 and cup 43. If an oil bath is employed in cup 43, it will, of course, serve to wash the air and insure better cleaning. The lateral extension 45 extends nearly the full length of the horizontal section 230i the air cleaner and its discharge end is in remote relationship to the outlet neck 31 on section 23 that communicates with the intake 46 of the carburetor 2, and, hence, the incoming air has to reverse its direction of fiow again before it can enter the carburetor, whereby to afford a final opportunity for the depositing of any dirt that might remain in the air to that point. It is on the top wall of the horizontal section 23 of the air cleaner that the air vents H are provided and these air vents are closely adjacent the outlet neck 31 leading to the carburetor intake 46. The reason for this location of these air vents l l is that hot gases delivered through the carburetor intake from the engine when the engine is stopped would otherwise be trapped in this chamber 41 defined be tween the top of the extension 45 and the top wall of the horizontal section 23 of the air cleaner. If these, hot gases were not permitted to escape and be replaced by fresh air, it would mean diificult starting if an effort was made to start the engine again while still hot and before the trapped hot gases referred to had an opportunity to cool oil or be dissipated or escape. Engines notoriously hard to start under such conditions have been found easy to start when equipped with my improved vacuum controlled air vent.

It is believed the foregoing description conveys a good understanding of the objects and advantages of my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

I claim:

1. In combination with a carburetor and an intake manifold for an internal combustion engine to which combustible mixture is supplied by the carburetor, and an air cleaner connected with the air intake opening of said carburetor, the improvement which consists in the provision of a vent for the carburetor to allow escape through said vent of hot gases discharged through the carburetor from said intake manifold upon stoppage of the engine, a movable closure for said vent, and vacuum operated means in communication with said intake manifold so as to be subject to reduction of pressure therein and mechanically connected with said closure to close said vent upon starting of the engine and open the same upon stopping.

2. The improvement set forth in claim 1 wherein said vacuum operated means includes spring means tending normally to return said closure to an extreme open position.

3. The improvement set forth in claim 1 wherein said vacuum operated means includes spring means tending normally to return said closure to an extreme open position, and retarding means to slow up the return movement of said closure.

4. The improvement set forth in claim 1 wherein said vacuum operated means includes, spring means tending normally to return said closure to an extreme open position, and a check valve between said vacuum operated means and said intake manifold seating toward said vacuum operated means, whereby the latter is not responsive to sudden rises in pressure in said manifold.

5. The improvement set forth in claim 1 wherein said closure is in the form of a pivoted flap valve and said vacuum operated means includes a cylinder and a piston reciprocable therein and pivotally connected to said closure, said cylinder oscillatably mounted infixed spaced relation to said closure andhaving its pivoted end in communication with the intake manifold and having a small air bleeder hole provided in the other end, there being spring means normally urging said piston toward the bleeder hole to open said closure.

6. The improvement set forth in claim 1 wherein said closure is in the form of a pivoted fiap valve and said vacuum operated means includes a cylinder and a piston reciprocable therein and pivotally connected to said closure, said cylinder oscillatably mounted in fixed spaced relation to said closure and having its pivoted end in communication with the intake manifold and having a small air bleeder hole provided in the other end, there being spring means normally urging said piston toward the bleeder hole to open said closure and a check valve in the line of communication between the pivoted end of said cylinder and said intake manifold seating toward the cylinder.

7. In a carburetor and air cleaner combination, wherein the air cleaner has an enclosed chamber and the carburetor has an air intake neck communicating with said chamber below the top wall thereof, the improvement which consists in the provision of vent openings in the top wall of saidchamber adjacent the intake neck to permit escape of hot gases discharged from the carburetor intake into said chamber 'upon stoppage of the engine that is supplied with combustible mixture by said carburetor, a closure for said vent openings, and means connected for operating said closure, so related to the operation of the carburetor in the starting and stopping of the engine to close said vent openings upon starting the engine and open the same upon stopping.

8. The improvement set forth in claim 7 including spring means tending normally to move said closure to open position.

9. In combination with a carburetor and an intake manifold for an internal combustion engine to which combustible mixture is supplied by the carburetor, the improvement which consists in the provision of a vent to allow escape of hot gases from the manifold upon stoppage of the engine, a movable closure for said vent, and means for automatically operating said closure for closing said vent upon starting of the engine and opening the same upon stopping.

10. The improvement set forth in claim 9 wherein said last mentioned means includes spring means tending normally to move said closure to open position, and movement checking means to slow up the opening movement of said closure.

11. The improvement set forth in claim 9 wherein said last mentioned means is operable in a closing direction in response to reduction in pressure in said manifold.

12. The improvement set forth in claim 9 wherein said last mentioned means is operable in a closing direction in response to reduction in pressure in said manifold,'s'aid means including spring means tending normally to move said closure to open position, a check valve adapted to seat outwardly relative to the manifold,

whereby to isolate said means from the manifold in event of sudden rises in pressure in the manifold.

13. The improvement set forth in claim 9 wherein said last mentioned means is operable in a closing direction in response to reduction in pressure in said manifold, said means including spring means tending normally to move said closure to open position, a check valve adapted to seat outwardly relative to the manifold, whereby to isolate said means from the manifold in event of sudden rises in pressure in the manifold and dashpot means to check the speed of opening movement of said closure under action of said spring means.

14. In combination With a carburetor and an intake manifold for an internal combustion engine to which combustible mixture is supplied by the carburetor, and an air cleaner connected with the air intake opening of said carburetor, the improvement which consists in the provision of a vent at the approximate junction of said air cleaner and said carburetor to allow escape through said vent of hot gases discharged through the carburetor from said intake manifold upon stoppage of the engine, a movable closure for said vent, and vacuum operated means in communication with said intake manifold so as to be subject to reduction of pressure therein and mechanically connected with said closure to close said vent upon starting of the engine and open the same upon stopping.

PAUL H. FITZGERALD.

N 0 references cited. 

